The synchronization device of the present invention is adapted for use in an articulated parallelogram boom assembly for elevating a work platform of the type disclosed in U.S. Pat. No. 4,019,604, dated Apr. 26, 1977. This elevating platform apparatus includes a vehicle for carrying the articulated parallelogram boom assembly and associated platform. The lower boom assembly includes parallel compression and tension arms extending between and pivotally connected to the vehicle and a floating frame. The upper boom assembly also includes compression and tension arms extending between and pivotally connected to the floating frame and an end frame upon which the platform is mounted. An extensible hydraulic cylinder is connected between the vehicle chassis frame and lower compression arm for pivoting the lower boom assembly relative to the vehicle frame, whereby the floating frame is elevated while maintaining a steady level altitude. A rigid tension link is interconnected between the upper and lower compression arms of the two boom assemblies so as to impart a moment force which pivots the upper boom assembly relative to the floating frame and in synchronization with the lower boom assembly as it pivots relative to the vehicle, whereby the work platform is maintained parallel to the ground throughout the luffing range of the boom assembly.
While the synchronization device of the aforementioned patent consists of a tension link, other articulated parallelogram boom assemblies have been constructed and arranged so that the synchronization devices consists of a compression link, or meshing gears operatively connected between the upper and lower arms of the two boom assemblies.
While each of the prior art synchronization devices has been satisfactory for its intended purpose, after considerable research and experimentation the synchronization device of the present invention has been devised for use in lieu of the aforementioned tension link, compression link or gears to provide a more synchronized movement of the upper and lower boom assemblies.